According to the transportation analytics firm INRIX, Boston has become the seventh-most congested urban area in the nation.

A 2018 Asthma and Allergy Foundation of America report listed Boston as the 11th most challenging place to live with asthma and ranked the city fourth nationally for asthma prevalence, with the state recording asthma rates at 10.2 percent for adults and 12.9 percent for children.

“Increasing traffic, if not met with big technological changes, will contribute to air pollution problems,” warned Boston University environmental health professor Jonathan Levy. “The good news is that air quality is better than it was 20 years ago. But technological solutions may not be able to keep up with the trend of population density.”

Air pollution costs the economy £22bn annually with some six million sick days

Toxic air can cause heart disease and major lung conditions such as asthma

Researchers found toxic air has been linked to conditions such as dementia

Scientists have found high levels of pollution inside domestic homes

British researchers warned that air pollution could be responsible for 60,000 cases of dementia in the UK. Scientists from St George’s University and King’s College London found that people living in areas polluted by traffic and industry are 40 per cent more likely to develop the condition.

The Reading research forecasts that toxic household air may cause an 80 per cent jump in the number of people with asthma within three decades.

Walking along quieter back streets rather than main roads can cut your exposure to vehicle exhaust pollution by more than half. Researchers at King’s College London discovered this last year by sending pedestrians on seven different routes through London. Some of the side roads had 60 per cent less pollution.